My Envoy revs real high before changing speeds and has low power. on 2002 GMC Envoy

water pump went out and I changed it the other night.. the check engine light stays on but the worst is now the motor revs real high before shifting and sounds like needs to shift again yet low power .. I check the fluid it has enough.. for about 2 seconds the low power light came on but not anymore.. and man is it sucking gas.. any ideas?/

the throttle body is bad.its electronically controlled by a gear case within the throttle body where the wiring plug connects.the gears are stripped causing the throttle body not to open.to check this remove the air chamber mounted on top of the intake connected to the throttle body to expose the throttle body flapper that controlls air intake.turn the key on but do not start the engine.leave the wiring harness connected.with the key on press the accellerator and observe the flapper.if it does not open this will comfirm that the electronically controlled gear is malfunctioning.....replace the throttle body.ifound a used one for 100 dollars.new one is around 250 dollars.